基于结晶收缩特性的连铸矩形坯成形曲线研究

Research on Profile Curve of Rectangular Billets in Continuous Casting Based on Solidification and Shrinkage Characteristics

针对传统连铸结晶器效率低、拉坯速度慢、铸坯表面及形状缺陷等问题,设计并加工了一种高效、高速、高质(Efficient,speedy and quality,ESQ)连铸结晶器内腔形线。基于矩形坯结晶器内传热和结晶收缩行为特性,推导并建立了结晶器铜管内腔形线几何模型,运算得到形线曲线表达式和锥度表达式。根据连铸坯热交换收缩组成模型,针对高碳钢材料大矩形坯规格修正原模型及表达式,将优化结果与钢厂传统形线对比分析。依托Matlab/GUI二次开发了结晶器形线尺寸输出系统,为现有钢厂设计并加工了230 mm×170 mm断面U71Mn钢种结晶器芯棒和铜管,保持其他连铸条件基本不变,使现有连铸机拉坯速度从1.1 m/min提高至1.6~1.7 m/min。结果表明,得到的连铸坯产品表面质量与原产品相近,且并无形状缺陷,验证了模型计算的合理性和正确性。相比于传统连铸结晶器内腔形线,新形线曲线提高了结晶器的换热效率,且保证了铸坯质量,这为增加连铸坯产量提供了基础。

To improve the problems in traditional continuous casting mold,such as low efficiency,slow speed and defective on the surface and shape of the billet,a profile curve is designed and manufactured in continuous casting mold,which is efficient,speedy and quality(ESQ).Based on the characteristics of heat transfer and solidified shrinkage in rectangular billets mold,a geometric model of profile curve in copper mold tubes is developed.Moreover,the calculation formula about profile curve and taper curve are solved.According to the model,which is the composition of heat transfer shrinkage in continuous casting,the original model and calculation formula are modified in high-carbon steel of large rectangular billets.The results optimized are compared with traditional profile curve.Based on Matlab/GUI,the output system for profile curve in copper mold tubes is obtained with the secondary development.The copper mold tubes and mould,applied for 230 mm×170 mm U71Mn steel in continuous casting,are designed and processed for the existing steel mill.If the other continuous casting conditions remains basically,the speed of existing continuous casting machine will increase from 1.1 m/min to 1.6-1.7 m/min.The result shows that the surface quality of continuous casting billets is similar to the original and no distortion,which verifies rationality and correctness of the model calculation.Compared with the profile curve in traditional continuous casting mold,new profile curve improves heat transfer efficiency in mold and ensures processing quality of billets,which provides better technical support for increasing number of billets.